1. Field
Example embodiments relate to a method of inspecting a mask and an apparatus for performing the same. More particularly, example embodiments relate to a method of inspecting a mask that may be used for forming a photoresist pattern on a semiconductor substrate, and an apparatus for performing the method.
2. Description of the Related Art
Generally, a photolithography process may be performed on a semiconductor substrate to form a pattern on the semiconductor substrate. For example, a layer may be formed on the semiconductor substrate. A photoresist film may be formed on the layer. A mask having a mask pattern may be arranged over the photoresist film. A light may be irradiated to the photoresist film through the mask to transcribe the mask pattern into the photoresist film. The photoresist film may be developed to form a photoresist pattern having a shape corresponding to the mask pattern. The layer may be etched using the photoresist pattern as an etch mask to form the pattern on the semiconductor substrate.
Because the pattern may have a shape corresponding to the mask pattern, it may be important to provide the mask pattern with a designed shape. The mask pattern may be obtained by forming a light-blocking layer on a mask substrate, and exposing the light-blocking layer using an electron beam.
Thus, whether the mask pattern may be normal or not may be determined in accordance with an electron beam irradiating apparatus for irradiating the electron beam to the light-blocking layer. As a result, a process for testing the electron beam irradiating apparatus may be performed.
According to a conventional method of inspecting a mask, an actual image, which may be obtained from a mask pattern formed by the electron beam irradiating apparatus, may be compared with a reference image to determine whether the mask pattern may be normal or not.
However, the conventional method using comparing the actual image with the reference image may have problems in view of determination accuracy. For example, a set of the reference image may have low reliability. Further, there may exist errors in an allowable range, which may be used for determining whether the actual image may be normal or not, set from the reference image.